1. Field of the Invention
This invention relates to fluid handling processes and apparatus. More particularly, this invention relates to fluidic oscillators and new methods and apparatus for improving their effective operating efficiencies.
2. Description of the Related Art
Fluidic inserts or oscillators are well known for their ability to provide a wide range of distinctive liquid sprays into surrounding ambient gaseous environments. The distinctiveness of these sprays is due to the fact that they are characterized by being oscillatory in nature, as compared to the relatively steady state flows that are emitted from standard spray nozzles.
FIG. 5 of the present Assignee's (USPN) U.S. Pat. No. 4,052,002 illustrates the oscillatory nature of the spray from a typical fluidic oscillator. It shows what can be considered to be the essentially temporally varying, two-dimensional, planar flow pattern of a liquid jet or spray that issues from the oscillator into a surrounding gaseous environment and breaks into droplets which are distributed transversely to the jet's general direction of flow. Such spray patterns may be described by the definable characteristics of their droplets (e.g., the volume flow rate of the spray, the spray's area of coverage or its fan angle, the spatial distribution of droplets in planes perpendicular to the direction of flow of the spray and at various distances in front of the oscillator's outlet, the average droplet velocities, the average size of the droplets, and the frequency at which the droplets impact on an obstacle in the path of the spray).
A fluidic insert is generally thought of as a thin, rectangular member that is molded or fabricated from plastic and has an especially-designed, uniform depth, liquid flow channel or fluidic circuit fabricated into either its broader top or bottom surface, and sometimes both. Pressurized liquid enters such an insert and is sprayed from it. See, for example the fluidic insert (18) and housing (10) in FIG. 1 of the present Assignee's U.S. Pat. No. 7,014,131.
There are many well known designs of fluidic circuits that are suitable for use with such fluidic inserts. Many of these have some common features, including: (a) at least one power nozzle configured to greatly accelerate the movement of the liquid that flows under pressure through the insert so that it separates from the walls downstream of the power nozzle so as to form an essentially “free” jet downstream of the power nozzle (i.e., “free” in that the jet as it exits the power nozzle is not attached to the sidewalls that are attached to the edges of the power nozzle), (b) an interaction chamber through which the liquid flows and in which the flow phenomena (e.g., intermittent, alternating vortices in side-by-side locations within the chamber) is initiated that will eventually lead to the spray from the insert being of an oscillating nature, (c) a liquid inlet, (d) a pathway that connects the inlet and the power nozzle/s, and (e) one or more outlets or throats from which the liquid sprays from the insert—see U.S. Pat. No. 4,231,519 for an example of a multiple throat oscillator.
Examples of fluidic circuits may be found in many patents, including the present Assignee's U.S. Pat. No. 3,563,462 (Bauer), U.S. Pat. No. 4,052,002 (Stouffer & Bray), U.S. Pat. No. 4,151,955 (Stouffer), U.S. Pat. No. 4,157,161 (Bauer), U.S. Pat. No. 4,231,519 (Stouffer), which was reissued as RE 33,158, U.S. Pat. No. 4,508,267 (Stouffer), U.S. Pat. No. 5,035,361 (Stouffer), U.S. Pat. No. 5,213,269 (Srinath), U.S. Pat. No. 5,971,301 (Stouffer), U.S. Pat. No. 6,186,409 (Srinath) and U.S. Pat. No. 6,253,782 (Raghu).
Most fluidic oscillators and fluidic circuits are fabricated so as to have lateral symmetry about their centerlines. However, there are instances in which asymmetries are built into fluidic oscillators. For example, when it is desired to impose a yaw angle or outward or lateral horizontal deflection on the centerline of the spray that flows from an oscillator, it is known to fabricate such an oscillator with an asymmetry relative to its centerline. See the present Assignee's U.S. Pat. No. 6,253,782.
As fluidic oscillators have continued to be used in more types of industrial applications, the need has been identified to improve upon their designs so as to enable them to achieve greater operating efficiencies and flow performances (e.g., higher mean exit velocities, larger fan angles and more uniform spatial distribution of their droplets). For example, for a certain size oscillator operating at a specified pressure to yield a spray having a required fan angle, a means is needed to modify such an oscillator so that its spray also has a higher mean velocity at the oscillator's exit.
3. Objects and Advantages
There has been summarized above, rather broadly, the prior art that is related to the present invention in order that the context of the present invention may be better understood and appreciated. In this regard, it is instructive to also consider the objects and advantages of the present invention.
It is an object of the present invention to provide an improved fluidic oscillator that can operate more efficiently than prior fluidic oscillators.
It is also an object of the present invention to provide fluidic oscillators that can provide specific types of desired sprays (e.g., those having higher mean exit velocities, larger fan angles and more uniform spatial distribution of their droplets) that have heretofore not been achievable with conventional fluidic technology.
It is a further object of the present invention to provide improved and more versatile fluidic inserts and their enclosures which are ideally designed for a wider, more demanding range of windshield washer applications.
It is an additional object of the present invention to provide improved enclosures and fluidic inserts that are ideally designed for an assortment of commercial cleaning applications.
It is an object of the present invention to provide enclosures for otherwise standard fluidic oscillators that allow a user to better direct and control the location of the areas being wetted by the sprays from such devices.
These and other objects and advantages of the present invention will become readily apparent as the invention is better understood by reference to the accompanying summary, drawings and the detailed description that follows.